Model-based cloth rendering is important for many applications such as online retail, textile design, and in entertainment applications like video games and movies. Despite a rich history in computer graphics, accurately modeling fabrics remains challenging in that fabrics are structurally and optically very complex, resulting in dramatic variations in their appearance under different conditions. Conventional fiber-based models based on micro-appearance modeling techniques capture the rich visual appearance of fabrics, but are too onerous to design and edit. Conventional yarn-based procedural models are powerful and convenient, but too regular and not realistic enough in appearance, as they lack fiber-level details that contribute significantly to overall appearance of a fabric.